Serialization
Enumerations are serialized differently from objects. Specifically, they have a new serialization code, "E" , that specifies the name of the enum case. The deserialization routine is then able to use that to set a variable to the existing singleton value. That ensures that:
<? php
Suit :: Hearts === unserialize ( serialize ( Suit :: Hearts ));
print serialize ( Suit :: Hearts );
// E:11:"Suit:Hearts";
?>
On deserialization, if an enum and case cannot be found to match a serialized value a warning will be issued and false returned.
If a Pure Enum is serialized to JSON, an error will be thrown. If a Backed Enum is serialized to JSON, it will be represented by its scalar value only, in the appropriate type. The behavior of both may be overridden by implementing JsonSerializable .
For print_r() , the output of an enum case is slightly different from objects to minimize confusion.
<? php
enum Foo {
case Bar ;
}
enum Baz : int {
case Beep = five ;
}
print_r ( Foo :: Bar );
print_r ( Baz :: Beep );
/* Produces
Foo Enum (
[name] => Bar
)
Baz Enum:int {
[name] => Beep
[value] => 5
}
*/
?>
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